SOCIAL CHANGE

in sociology, the alteration of mechanisms within the social structure, characterized by changes in cultural symbols, rules of behaviour, or value systems. Throughout its historical development, sociology has borrowed models of social change from other fields. In the late 19th century, when evolution became the predominant model for understanding biological change, ideas of social change took on an evolutionary cast, and, though other models have refined modern notions of social change, evolution remains often an underlying principle. Other sociological models created analogies between social change and the West's technological progress. In the mid-20th century, anthropologists borrowed from the theory of structuralism to elaborate an approach to social change called structural functionalism. This theory postulated the existence of certain basic institutions (including kinship relations and division of labour) that determine social behaviour. Change in one institution affects other institutions because they function interdependently. Marxist economic theory concluded that social change is the result of various social classes within a culture vying for power. This conflict theory and the structural-functional theory represent two sides of the same coin. Although both agree that social change and structure are mutually interdependent, the conflict model stresses the process of change while the structural-functional model focuses on the elements of stability. Social change can evolve from a number of different sources, including changes in the ecosystem (which can cause the loss of natural resources or widespread disease); technological change (epitomized by the Industrial Revolution, which created a new social group, the urban proletariat); population growth and other demographic variables; and ideological, economic, and political movements.